Validating a novel index (SWAT-Bp) to predict mortality risk of community-acquired pneumonia in Malawi

Abstract

BackgroundCommunity-acquired pneumonia is a major cause of mortality worldwide. Early assessment and initiation of management improves outcomes. In higher-income countries, scores assist in predicting mortality from pneumonia. These have not been validated for use in most lower-income countries.AimTo validate a new score, the SWAT-Bp score, in predicting mortality risk of clinical community-acquired pneumonia amongst hospital admissions at Queen Elizabeth Central Hospital, Blantyre, Malawi.MethodsThe five variables constituting the SWAT-Bp score (male [S]ex, muscle [W]asting, non-[A]mbulatory, [T]emperature (>38°C or <35°C) and [B]lood [p]ressure (systolic<100 and/or diastolic<60)) were recorded for all patients with clinical presentation of a lower respiratory tract infection, presumed to be pneumonia, over four months (N=216). The sensitivity and specificity of the score were calculated to determine accuracy of predicting mortality risk.ResultsMedian age was 35 years, HIV prevalence was 84.2% amongst known statuses, and mortality rate was 12.5%. Mortality for scores 0–5 was 0%, 8.5%, 12.7%, 19.0%, 28.6%, 100% respectively. Patients were stratified into three mortality risk groups dependent on their score. SWAT-Bp had moderate discriminatory power overall (AUROC 0.744). A SWAT-Bp score of ≥2 was 82% sensitive and 51% specific for predicting mortality, thereby assisting in identifying individuals with a lower mortality risk.ConclusionIn this validation cohort, the SWAT-Bp score has not performed as well as in the derivation cohort. However, it could potentially assist clinicians identifying low-risk patients, enabling rapid prioritisation of treatment in a low-resource setting, as it helps contribute towards individual patient risk stratification.

Validity of Pneumonia Severity Assessment Scores in Africa and South Asia: A Systematic Review and Meta-Analysis

“…The eligible 11 studies were published between 2008 and 2019, with a total of 3740 patients from 7 LMICs. Eight studies were conducted in Africa (Malawi [ 18 , 19 , 34 ], Nigeria [ 30 ], South Africa [ 29 , 33 ], Uganda [ 17 ] and Egypt [ 35 ]), and three were from South Asia (Pakistan [ 32 ] and India [ 31 , 36 ]). The average age of the patients ranged from 34 to 69.9 years, and male percentage varied between 38.6% and 62.1%.…”

“…A total of 12 scores, CURB-65 [ 30 , 31 , 32 , 33 , 34 , 35 ], CRB-65 [ 19 , 29 , 30 , 32 , 33 , 34 ], PSI [ 31 , 36 ], SWAT-Bp [ 18 , 19 , 34 ], CURB-45 [ 33 ], SCAP [ 35 ], ADL score [ 35 ], modified IDSA/ATS criteria [ 34 ], Koss et al tool [ 17 ], CTA [ 33 ], ACHU [ 33 ] and SMRT-CO [ 34 ], were examined in these 11 studies, 7 of which reviewed the performance of more than one score [ 19 , 30 , 31 , 32 , 33 , 34 , 35 ]. All studies addressed mortality as either in-hospital [ 18 , 19 , 33 ], 30-day [ 17 , 30 , 32 , 34 , 35 ], in-hospital or within 30 days of discharge [ 31 , 36 ] or in-hospital or within 14 days following emergency department visit for those discharged earlier [ 29 ]. Four studies included other outcomes (ICU admission [ 30 , 31 ], mechanical ventilation [ 35 ], hospitalisation and time to clini...…”

“…Only one study exclusively evaluated elderly patients (≥60 years) admitted to ICU [35]. A total of 12 scores, CURB-65 [30][31][32][33][34][35], CRB-65 [19,29,30,[32][33][34], PSI [31,36], SWAT-Bp [18,19,34], CURB-45 [33], SCAP [35], ADL score [35], modified IDSA/ATS criteria [34], Koss et al tool [17], CTA [33], ACHU [33] and SMRT-CO [34], were examined in these 11 studies, 7 of which reviewed the performance of more than one score [19,[30][31][32][33][34][35]. All studies addressed mortality as either inhospital [18,19,33], 30-day [17,30,32,34,35], in-hospital or within 30 days of discharge [31,36] or in-hospital or within 14 days following emergency department visit for those discharged earlier [29].…”

“…The eligible 11 studies were published between 2008 and 2019, with a total of 3740 patients from 7 LMICs. Eight studies were conducted in Africa (Malawi [18,19,34], Nigeria…”

“…Such tools may be less suitable for use in LMICs since they have been derived from a HIC population with different population characteristics, such as age and ethnicity, comorbidity (including coinfection with HIV), nutritional status and tuberculosis prevalence/clinical overlap [ 13 , 14 , 15 , 16 ]. To date, we believe there has not been a comprehensive evaluation of the validity of CAP scoring tools in LMIC populations, despite some evidence showing their poor performance [ 8 , 17 , 18 ]. CRB-65 performed poorly in a Malawian hospital, where it was insensitive to predicting mortality compared to a locally developed score [ 19 ].…”